A hydraulic piston engine is known from European Patent Reference EP-A1-0 567 805, having a number of axial cylinders, which are circumferentially arranged in a rotatable cylinder barrel. Each of the cylinders is provided with a channel, which alternatingly communicates with an inlet port or an outlet port in a housing. From this reference it is apparent that the dimension of the channel in the radial direction of the cylinder barrel is considerably less than the diameter of the cylinder assuming that the channel has a circular cross sectional shape. The cross sectional area of the channel is also considerably less than the cross sectional area of the corresponding cylinder. The result is that the maximum flow capacity of the cylinders and the total capacity of the engine is not fully utilized.
The object of the present invention is to provide a hydraulic rotating axial piston engine of the above discussed type having maximum flow capacity for a certain volume of the cylinders.
The present object is obtained by means of an engine according to the present invention, where the channels open to the cylinders along the peripheral wall of each cylinder. The opening to the cylinders has substantially the same area as the area of the ports of the barrel and extends completely outside the nearest end position of the piston in each cylinder.
The hydraulic rotating axial piston engine of the present invention has a housing enclosing a cylinder barrel journalled in the housing for rotation around a barrel axis, and a number of circumferentially arranged cylinders in the barrel with a number of pistons reciprocating between two defined end positions. The pistons cooperate with an angled plate in order to obtain the reciprocating movement. The axial piston engine has an input/output shaft. The cylinder barrel has channels connecting each cylinder to ports in the cylinder barrel, the ports alternatively acting as inlet and outlet ports. The housing has at least one inlet and outlet channel, each having a kidney shaped port, facing towards the inlet and outlet ports of the cylinder barrel. The kidney shaped ports communicate with a number of the ports at the barrel. At least a number of the cylinder barrel ports extend in both directions outside the cylinders in the two circumferential directions of the cylinder barrel.
Further features of the present invention will become apparent to those skilled in the art upon reviewing the following specification and attached drawings.